Bacteremia caused by an Enterococcus faecalis isolate with high-level linezolid resistance in a teenager with Crohn's disease

Diphosphonium ionic liquids as broad-spectrum antimicrobial agents

PURPOSE

One of the most disturbing trends in recent years is the growth of resistant strains of bacteria with the simultaneous dearth of new antimicrobial agents. Thus, new antimicrobial agents for the use on the ocular surface are needed.

METHODS

We synthesized a variety of ionic liquid compounds, which possess 2 positively charged phosphonium groups separated by 10 methylene units in a "bola"-type configuration. We tested these compounds for antimicrobial activity versus a variety of ocular pathogens, as well as their cytoxicity, in vitro in a corneal cell line and in vivo in mice.

RESULTS

The ionic liquid Di-Hex C10 demonstrated broad in vitro antimicrobial activity at low micromolar concentrations versus gram-negative and gram-positive organisms, including methicillin-resistant Staphylococcus aureus strains and ocular fungal pathogens. Treatment with Di-Hex C10 resulted in bacterial killing in as little as 15 minutes in vitro. Di-Hex C10 showed little cytotoxicity at 1 μM versus a corneal epithelial cell line or at 10 μM in a mouse corneal wound model. We also show that this bis-phosphonium ionic liquid structure is a key because a comparable monophosphonium ionic liquid is cytotoxic to both bacteria and corneal epithelial cells.

CONCLUSIONS

Here, we report the first use of dicationic bis-phosphonium ionic liquids as antimicrobial agents. Our data suggest that diphosphonium ionic liquids may represent a new class of broad-spectrum antimicrobial agents for the use on the ocular surface.

Changes of faecal microbiota in patients with Crohn's disease treated with an elemental diet and total parenteral nutrition

BACKGROUND

Intestinal microbiota contributes to the pathogenesis of Crohn's disease. Elemental diet and total parenteral nutrition are effective therapies for Crohn's disease; however, changes of microbiota as a result of both treatments have not been fully elucidated.

AIM

To elucidate changes of faecal microbiota in Crohn's disease patients treated with elemental diet and total parenteral nutrition.

METHODS

Stool samples were collected from 33 active Crohn's disease patients and 17 healthy subjects, and recollected after elemental diet (8 patients) and total parenteral nutrition (9 patients). Terminal restriction fragment length polymorphism analysis of bacterial 16srDNA was performed to evaluate the whole microbiota. Specific quantitative PCR was then used to determine populations of predominant bacterial groups.

RESULTS

In Crohn's disease patients, the number of terminal restriction fragments, which reflects bacterial species, was significantly lower. Populations of total bacteria and Bifidobacterium were significantly lower and the ratio of Enterococcus was higher. The number of terminal restriction fragments was significantly decreased after total parenteral nutrition, but not after elemental diet. Population of Bacteroides fragilis significantly decreased after elemental diet, while population of Enterococcus significantly increased after total parenteral nutrition.

CONCLUSION

Faecal microbiota in Crohn's disease patients was markedly different from healthy subjects. Species diversity was reduced by total parenteral nutrition, but not by elemental diet.